def get_breadcrumb(cat3):    """包装面包屑导航数据"""    # 包装面包屑导航数据    breadcrumb = {}    breadcrumb['cat3'] = cat3    breadcrumb['cat2'] = cat3.parent    cat1 = cat3.parent.parent    cat1.url = cat1.goodschannel_set.all()[0].url    breadcrumb['cat1'] = cat1    return breadcrumb